Perspective: the KT event

As we continue to learn about what's influenced climate and life over the entire span of Earth's history, we discussed the following graph depicting Earth's temperature over the past 500 million years, starting with the Cambrian period (a time when complex life forms finally emerged on Earth, after it recovered from the dramatic "Snowball Earth" ice age discussed previously):

Paleotemperature graph from Wikipedia

In particular, we looked at sudden and dramatic temperature shifts and tried to figure out what prompted them. Did the overabundance of oxygen in the atmosphere at the end of the Carboniferous Period generate the Permian ice age? Were the Siberian Traps volcanic eruptions at the origin of the dramatic warming that followed? What was the effect of the KT asteroid impact on climate?

We also learned about the Cretaceous Tertiary (KT) event, which brought about the demise of dinosaurs by watching the fourth and last episode of Prehistoric Disasters: Asteroid strike from the Discovery Channel.

Watch this compilation of videos of the Chelyabinsk meteor, which hit the Ural region in Russia three years ago. It is estimated that it measured 20 meters in diameter when it entered Earth's atmosphere: very small in comparison to the 10 kilometers-wide asteroid that struck the earth during the KT event.

Perspective: the Siberian Traps

 picture from BBC.com

- What happened 250 Million years ago during the million year long volcanic eruption of the Siberian Traps? What gases came out of volcanoes, and what was their effects on the composition of the atmosphere and of the oceans? What chain reaction led to sudden global warming? What happened to life under those extreme conditions?

We'll answer those questions by watching and discussing the third episode of Prehistoric Disasters: Planet of Fire from the Discovery Channel.

Read the article on BBC Earth

Action: habitat restoration

In this lesson we took a first step toward intentionally designing our campus as a habitat garden for beneficial species. We learned about the iconic North American Monarch butterfly, about the reasons for its recent population decline, and planted Milkweed on campus in order to create a Monarch way station right here at MPH, thereby linking our campus to the Monarch migration corridor.

 AD is extracting seeds from a Milkweed pod.

Students are planting their seeds on the sunny hill overlooking the lower soccer field.

The next day, students are planting Milkweed along the nature trail.

Thank you to Ms. Cousins, who provided us with Milkweed pods for this experiment.

Perspective: Snowball Earth

 Snowball Earth, picture from NASA

- What triggers an ice age, and a period of warming? What happened 650 million years ago, when the earth became "snowball earth", covered in ice from the poles to the equator? How did it impact life? Was it a factor in the rise of multi-cellular organisms, and the ensuing Cambrian explosion?

We'll answer those questions by watching and discussing the second episode of Prehistoric Disasters: Snowball Earth from the Discovery Channel.